SUMMARY
Volatile anesthetics, like most drugs, undergo metabolism in the
body and are sometimes associated with toxic reactions. Scientific investigations
and industry research
have led to the development of more stable anesthetics with more desirable clinical
properties. The inhaled agents that are more heavily metabolized are associated
with the greatest numbers of reported toxicities. As with most drugs, these toxicities
occur when the anesthetics are given as standard-dose medications (i.e., the appropriate
medication and dose are given at the proper time, in the correct manner to the right
patient). These associated toxicities under most circumstances meet the definition
of adverse drug reactions. For comparison, 51% of approved drugs have serious adverse
drug reactions not detected before approval, and adverse drug reactions are responsible
for 6% of all hospital admissions, occur in 10% to 20% of hospitalized patients,
and are the cause of death of 0.1% of medical and 0.01% of surgical patients. They
are the fourth leading cause of death in hospitalized patients (0.32% of hospitalized
patients). Compared with most therapeutic agents, the safety of fluorinated inhaled
anesthetics is remarkable.
The use of any anesthetic must be based on specific knowledge
of its benefits and risks, how it may produce toxicity, and in which patients it
may be most safely administered. The perfect anesthetic agent does not exist, and
the circumstances of individual patients will continue to dictate the choice and
use of inhaled anesthetics in clinical practice. As ongoing research attempts to
uncover emerging toxicities, the clinician is challenged to balance new information
with current clinical practices and choose the safest, most effective agents for
each patient.
